Sound-amplifying means



April 13 1926. 1,580,418

J. E. DAvls 1 S OUND AMPLIFYING MEANS Filed Jan. 26, 1924 j Llll M149@ 4 'I *l gg"- i 6? Patented Apr. 13, 1926.

UNITED STATES JOHN E. DAVIS, OF BROOKLYN, NEW YORK.

SOUND-AMPLIFYING MEANS.

. Application led January 26, 1924. Serial No. 688,714.

T o all whom t may COW/cern:

Be it known that I, J oHN E. DAVIS, a citizen of the United States, and a resident of the borough of Brooklyn, in the county `of Kings, city and State of New York, have invented certain new and useful Improvements in Sound-simplifying Means, of which the following is a specification.

This invention relates to means to amplify Sound waves caused by the human voice or by the vibratory diaphragm of a sound reproducing device, telephone, radio receiving apparatus and other acoustic devices, and it is the object of the invention to provide a sound amplifier of this character which is novel, compact and cheap in structure, and highly efficient in the enhancing and propagating of sound waves, and which is capable of absorbing distorted sound waves of overtones and magnifying the sound waves of dominant and undertones.

In carrying out the invention I provide a tubular receiver for the sound waves which are to be augmented and magnified and arrange a vibratory wall in spaced relation around said receiver. This wall is preferably of truncated cone shape and rectangular shape in cross section with the small end closed and supported practically without stress or strain. This wall is in the nature of a sounding board for which purpose it isl preferably made of relatively thin wood having alternate relatively hard and'soft or spongy growth rings quarter sawed across the natural growth rings whereby said.

growth rings or grain will extend longitudinally and in the structure of the amplifier extend in parallelism and longitudinally of the axis of the conical member. The sound receiver is connected to and supported from the conical member intermediate its ends and sides and through which means the sound waves entering the receiver are transmittedto the sounding board to vibrate the latter in consonance therewith the dominant tones of such sound vibrations being magnified by the hard layers of the growth rings of the wood and the overtones being absorbed in the soft spongy layers alternatinowith said hard layers. The receiving end of the receiver is preferably arranged at the open end of the conical member and extends axially of and'to adjacent the closed end of said conical member, the sound waves 'emerging from the outlet end of the receiver being impinged against the closed end of the conical member and thereby relexed outward and act to exert a Adirective force outward from the conical member and of the waves set up by the vibration thereof and transmitted thereto from the receiver.

In the drawing accompanying and forming a part of this specification, I have shown an embodiment of the invention in which Figure 1 is a longitudinal sectional view and showing the manner of mounting the same, and

Figure 2 is a perspective view with a part of the mounting and enclosing casing removed and a part thereof shown in section.

The embodiment of the invention illustrated in the drawing comprises a truncated cone shaped member 3, preferably of rectangular shape in cross section, which member is constructed of wood having alternating relative hard and soft spongy growth rings, spruce being preferred and having been found to function eiiiciently for the purpose, although it is to be understood that other wood having the same growth characteristics may be utilized, said wood being quarter sawed or sawed across the natural growth rings whereby the grain of the wood or board will extend in parallel relation longitudinally of the board, and in the structure of the conical member said grain will extend longitudinally o-f the axis thereof. The smaller end of said member 3 has a closure et of wood attached thereto which may also be of the same material as the side walls.

A tubular receiver 5, which is also preferably of conical form, the wall diverging from the receiving end 6 to the opposite end 7, and of rectangular shape in cross section, .is mounted in the truncated cone sounding board 3 to extend thereinto from the en- `larged end to adjacent but in spaced relation to the closed end `ai, the receiving end being at the larger open end of the conical member with the latter extending around and in spaced relation to the. receiver as clearly shown in the drawing. The receiver is also made of wood having a grain consisting of alternating hard land soft or spongy layers extending longitudinally thereof.

Totransmit the vibrations set up in the receiver by the transmission of sound waves wise between the receiver and conica memed'oe intermediate its ends, as at 9, whereby on y a relatively small part of said edge of the bridge pieces and at opposite ends willv engage with the wall of the sounding board. The receiver and bridge pieces are held in position relativel to the sounding board substantially without stress or strain, screws 10 being shown for ,this purposel passing through the sounding board and engaging in the bridge pieces.

In order that the amplifier will function properly the amplifying unit, comp-rising the conical sounding board with the sound wave receiver, is mounted in a support without stress or strain upon the vibrato-ry actions of the sounding board for which purpose it is mounted at the outer or enlarged en-d of the conical member. In the pree`nt instance it is mounted in a carrying casing 11 extending .around in spaced relation and closing the sides and closed end of the conical member and having an open end at the enlarged open end` of the con-ical member the latter being secured in said casing by screws 12 passing through the edge portion of the conical member substantially midway between the sides and engaging in the casing with .a cushioning member 13 interposed between the conical member and casing, as clearly shown in the drawing. A grille 14 may be attached to the open end 'of the casing` and amplifier.

The amplifier. may be used as amega- .phone for augmenting and magnifying the sound of the human voice directly in whichl case the user talks directly into the receiving end 6 of the receiver 5.A To use the device for amplifying reproducedvsounds, as by a vibratory diaphragm either mechanically or electrically operated, a diaphragm carrier or microphonic unit, designated in a general way at 15', is mounted directly in the receiving end of the receiver, for which purpose a reinforcement, as shown at 14', is arranged at the receiving end ofthe receiver, this reinforcement means consisting of a layer of wood similar to the material of which lthe receiver is made with the grain extending longitudinally of the receiver.

*While I have illustrated and described one manner -of construction anduarrangement of my improved sound amplifier `it will lbe obvious that the invention-is not to be limited to such construction and arrangement and that variations and modifications may be made in structure and form ,and that portions of the invention may be used with` out others and come within the scope of the invention.

Having thus described my invention I cl-aim: y

1. In a 'sound amplifier, a sounding board of truncated cone shape closed at the smaller end, a sound receiver axially of thesounding boa-rd with the sound receiving end at the open end thereof, and a bridge connection between the sounding board and the receiver through which the vibrations of the sound waves are transmitted from the receiver toy the board, said sounding board being supported at the open end only.

,2. In a sound amplifier, a sounding board of truncated c one sha-peihaving a closure at oneend, a tubular sound receiver extending into the sounding boa-rd axially thereof to adjacent the closed end and having the receiving end a-t the open end of the .sounding board, means to connect the receiver to and support the same from the sounding board intermedi-ate the ends to transmit the `sound vibrations therethrough from the receiver to the sounding board and reflex said sound waves outwardly, and means to support the sounding board at the open end substantially without stress or strain.l v

3. In a sound amplifier, a member of rectangular shape in cross section having one end closed, said member being constructed of quarter -sawed wood with the gra-in extending in parallel relation and longitudinally of the -axisthereof, -a tubular sound wave receiver to extend axially into saidA member to adjacent the closed end and with the receiving end at the open end of said member, bridge pieces to connect and support the receiver from said member between the ends thereof constructedand arranged to transmit the vibrations of the sound waves from the receiver to the wall of said member, an open end casinginwhich the rectangular member'is sup-ported substantially without stress or strain at the open end with said end at the open end of the casing, and an open grille closure for the open end of the casing. l v

Signed at New York city, in the county of New York and State'of New York this 23rd day ofJanuary, '1924. j

l Y JOHN fE. DAVIS, 

